Various embodiments relate generally to improvements for mechanical aerators in the form of a composite shaft and coupling that reduces transmission of vibrational energy. More particularly, embodiments are drawn to a composite aspirator shaft and/or coupling for mixing and adding air to wastewater.
Prior art wastewater aspirator shafts typically use a stainless steel aspirator shaft, as illustrated at reference numeral 9 in FIG. 3 of commonly-assigned U.S. Pat. No. 5,484,524.
Russian Patent No. 2176991 to Smirnov et al. discloses a tubular aerator that has a two layer reticular frame that is made of fiberglass and has a dispersing material sandwiched between the two coaxial layers of the fiberglass reticular frame. The fiberglass frame is described as being “air-permeable.” It is intended for use in a waste water system.
German Patent No. 19835100 to Spitzenberg et al. discloses a shaft intended for use in a waste water system, the shaft having fiberglass as one intermediate layer that is bonded to a concrete overlying layer by gravel embedded in the resin of the fiberglass layer.
U.S. Pat. No. 3,669,422 to Nogaj discloses an aerator for use in waste water treatment. The general desirability of fiberglass parts is taught.
U.S. Pat. No. 4,157,303 to Yoshikawa et al. discloses a waste water impeller that is made from fiberglass reinforced plastic.
International Patent Application Publication No. WO 97/40273 by Wood et al. discloses a progressive cavity pump having a flexible shaft formed from fiberglass.
U.S. Pat. No. 4,035,856 to Oberg discloses a marker flag with a shaft formed of fiberglass. It is taught that fiberglass has a modulus of elasticity of 3 to 4 million.
U.S. Pat. No. 4,363,603 to Petersen, U.S. Pat. No. 5,011,520 to Carr et al., and U.S. Pat. No. 5,174,877 to Cooper et al. disclose an impeller made from fiberglass.
U.S. Pat. No. 5,573,656 to Santos discloses use of a fiberglass coated steel roller or propeller to mix intermediate sludge materials in making asphalt.
U.S. Pat. No. 4,070,423 to Pierce discloses a waste water aeration apparatus that has a vertical tube disclosed as being formed of fiberglass.
U.S. Patent Application Publication No. 2005/0218074 by Pollock discloses a waste water purification apparatus having a downcomer structure formed of fiberglass.